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    <title>Document</title>
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    // 经由构造函数创建的实例化对象
    var arr = new Array();
    var str = new String();
    var obj = new Object();
    var p = new Promise(function () { });
    console.log(arr);
    console.log(str);
    console.log(obj);


    // instanceof    判断一个数据是否是由某个构造函数创建的(以后在拓展)
    console.log(arr instanceof Array);
    console.log(str instanceof String);
    console.log(obj instanceof Object);
    console.log(p instanceof Promise);

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